package com.itheima.web.servlet;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

/**
 * 替换HttpServlet，根据请求的最后一段路径来进行方法分发
 */
public class BaseServlet extends HttpServlet {
    //根据请求的最后一段路径来进行方法分发
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1.获取请求路径
        String uri = req.getRequestURI();// /brand-case/brand/selecetAll
        //System.out.println(uri);
        //2.获取最后一段路径，方法名
        int index=uri.lastIndexOf('/');
        String methodName = uri.substring(index+1);   //  /selectAll? selectAll?
       // System.out.println(methodName);

        //2.执行方法
        //2.1获取BrandServlet/UserServlet字节码对象 Class
        //谁调用我(this 所在方法),我(this)代表谁
       // System.out.println(this);   //BrandServlet? HttpServlet? BrandServlet!
        Class<? extends BaseServlet> cls = this.getClass();
        //2.2获取方法 Method对象
        try {
            Method method = cls.getMethod(methodName, HttpServletRequest.class, HttpServletResponse.class);
            //2.3执行方法
            method.invoke(this, req, resp);
        } catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException e) {
            e.printStackTrace();
        }

    }
}
